Okay kiddo, so "cheonmin" is a Korean word that means "lowly people" or "common people". It refers to people who are not part of the upper class or nobility. These are the regular folks who work hard every day to provide for themselves and their families. They might be farmers, artisans, or laborers. They are important because without them, society wouldn't function properly. Even though they might not have the same fancy clothes, big houses, or expensive possessions as the rich people, they are still valuable and deserve respect. So basically, cheonmin are just normal people like you and me, who work hard and contribute to the community.